// 2007-08-01
// xcore_md5.cpp
// 
// MD5支持类


#include "xcore_md5.h"
#include "xcore_byte_order.h"

namespace xcore {

// Constants for MD5 Transform.
#define S11 7
#define S12 12
#define S13 17
#define S14 22
#define S21 5
#define S22 9
#define S23 14
#define S24 20
#define S31 4
#define S32 11
#define S33 16
#define S34 23
#define S41 6
#define S42 10
#define S43 15
#define S44 21

// F, G, H and I are basic MD5 transformations functions.
#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
#define G(x, y, z) (((x) & (z)) | ((y) & (~z)))
#define H(x, y, z) ((x) ^ (y) ^ (z))
#define I(x, y, z) ((y) ^ ((x) | (~z)))

// ROTATE_LEFT rotates x left n bits.
#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))

// Rounds 1, 2, 3, and 4 MD5 transformations.
// Rotation is seperate from addition to prevent recomputation.
#define FF(a, b, c, d, x, s, ac) { \
 (a) += F ((b), (c), (d)) + (x) + (uint32)(ac); \
 (a) = ROTATE_LEFT ((a), (s)); \
 (a) += (b); \
  }

#define GG(a, b, c, d, x, s, ac) { \
 (a) += G ((b), (c), (d)) + (x) + (uint32)(ac); \
 (a) = ROTATE_LEFT ((a), (s)); \
 (a) += (b); \
  }

#define HH(a, b, c, d, x, s, ac) { \
 (a) += H ((b), (c), (d)) + (x) + (uint32)(ac); \
 (a) = ROTATE_LEFT ((a), (s)); \
 (a) += (b); \
  }

#define II(a, b, c, d, x, s, ac) { \
 (a) += I ((b), (c), (d)) + (x) + (uint32)(ac); \
 (a) = ROTATE_LEFT ((a), (s)); \
 (a) += (b); \
  }

static unsigned char md5_padding[64] =
{
 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
};

////////////////////////////////////////////////////////////////////////////////
// class XMD5
////////////////////////////////////////////////////////////////////////////////
XMD5::XMD5()
{
	initialize();
}

/// md5::Init
/// Initializes a new context.
void XMD5::initialize(void)
{
	m_count[0] = 0;
    m_count[1] = 0;

    m_state[0] = 0x67452301;
    m_state[1] = 0xEFCDAB89;
    m_state[2] = 0x98BADCFE;
    m_state[3] = 0x10325476;
}

/// XMD5::Update
/// MD5 block update operation. Continues an MD5 message-digest
/// operation, processing another message block, and updating the
/// context.
void XMD5::update(const uint8 *input, uint32 inputLen)
{
	uint32 i, index, partLen;

	if (input == NULL) return;

	// Compute number of bytes mod 64.
	index = (uint32)((m_count[0] >> 3) & 0x3F);

	// Update number of bits.
	if ((m_count[0] += (inputLen << 3)) < (inputLen << 3))
	{
		m_count[1]++;
	}
	m_count[1] += (inputLen >> 29);

	partLen = 64 - index;

	// Transform as many times as possible.
	if (inputLen >= partLen)
	{
		memcpy( &m_buffer[index], input, partLen );
		_transform( m_buffer );
	
		for (i = partLen; i + 63 < inputLen; i += 64)
		{
			_transform( &input[i] );
		}

		index = 0;
	}
	else
	{
		i = 0;
	}

	// Buffer remaining input.
	memcpy( &m_buffer[index], &input[i], inputLen - i );
}

/// XMD5::Finalize
/// MD5 finalization. Ends an MD5 message-digest operation, writing
/// the message digest and zeroizing the context.
void XMD5::final(uint8 (&digest)[16])
{
	uint8 bits[8];
	uint32 index, padLen;

	// Save number of bits.
	_encode( bits, m_count, 2 );

	// Pad out to 56 mod 64.
	index = (uint32)((m_count[0] >> 3) & 0x3f);
	padLen = (index < 56) ? (56 - index) : (120 - index);
	update( md5_padding, padLen );

	// Append length (before padding).
	update( bits, 8 );

	// Store state in digest
	_encode( digest, m_state, 4 );

	// Zeroize sensitive information.  ???
	memset(m_count, 0, 2 * sizeof(uint32));
	memset(m_state, 0, 4 * sizeof(uint32));
	memset(m_buffer,0, 64 * sizeof(uint8));
}

/// XMD5::Finalize
string XMD5::final()
{
	char buf[33];
	uint8 digest[16] = {};

	final(digest);

	for (int i = 0; i < 16; i++)
	{
		sprintf(buf + i * 2, "%02X", digest[i]); 
	}
	buf[32] = '\0';
	return buf;
}

/// XMD5::Transform
/// MD5 basic transformation. Transforms state based on block.
void XMD5::_transform(const uint8 *block)
{
	uint32 a = m_state[0], b = m_state[1], c = m_state[2], d = m_state[3], x[16];

	_decode( x, block, 64 );

	// Round 1
	FF (a, b, c, d, x[ 0], S11, 0xd76aa478); /* 1 */
	FF (d, a, b, c, x[ 1], S12, 0xe8c7b756); /* 2 */
	FF (c, d, a, b, x[ 2], S13, 0x242070db); /* 3 */
	FF (b, c, d, a, x[ 3], S14, 0xc1bdceee); /* 4 */
	FF (a, b, c, d, x[ 4], S11, 0xf57c0faf); /* 5 */
	FF (d, a, b, c, x[ 5], S12, 0x4787c62a); /* 6 */
	FF (c, d, a, b, x[ 6], S13, 0xa8304613); /* 7 */
	FF (b, c, d, a, x[ 7], S14, 0xfd469501); /* 8 */
	FF (a, b, c, d, x[ 8], S11, 0x698098d8); /* 9 */
	FF (d, a, b, c, x[ 9], S12, 0x8b44f7af); /* 10 */
	FF (c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */
	FF (b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */
	FF (a, b, c, d, x[12], S11, 0x6b901122); /* 13 */
	FF (d, a, b, c, x[13], S12, 0xfd987193); /* 14 */
	FF (c, d, a, b, x[14], S13, 0xa679438e); /* 15 */
	FF (b, c, d, a, x[15], S14, 0x49b40821); /* 16 */

	// Round 2
	GG (a, b, c, d, x[ 1], S21, 0xf61e2562); /* 17 */
	GG (d, a, b, c, x[ 6], S22, 0xc040b340); /* 18 */
	GG (c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */
	GG (b, c, d, a, x[ 0], S24, 0xe9b6c7aa); /* 20 */
	GG (a, b, c, d, x[ 5], S21, 0xd62f105d); /* 21 */
	GG (d, a, b, c, x[10], S22,  0x2441453); /* 22 */
	GG (c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */
	GG (b, c, d, a, x[ 4], S24, 0xe7d3fbc8); /* 24 */
	GG (a, b, c, d, x[ 9], S21, 0x21e1cde6); /* 25 */
	GG (d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */
	GG (c, d, a, b, x[ 3], S23, 0xf4d50d87); /* 27 */
	GG (b, c, d, a, x[ 8], S24, 0x455a14ed); /* 28 */
	GG (a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */
	GG (d, a, b, c, x[ 2], S22, 0xfcefa3f8); /* 30 */
	GG (c, d, a, b, x[ 7], S23, 0x676f02d9); /* 31 */
	GG (b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */

	// Round 3
	HH (a, b, c, d, x[ 5], S31, 0xfffa3942); /* 33 */
	HH (d, a, b, c, x[ 8], S32, 0x8771f681); /* 34 */
	HH (c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */
	HH (b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */
	HH (a, b, c, d, x[ 1], S31, 0xa4beea44); /* 37 */
	HH (d, a, b, c, x[ 4], S32, 0x4bdecfa9); /* 38 */
	HH (c, d, a, b, x[ 7], S33, 0xf6bb4b60); /* 39 */
	HH (b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */
	HH (a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */
	HH (d, a, b, c, x[ 0], S32, 0xeaa127fa); /* 42 */
	HH (c, d, a, b, x[ 3], S33, 0xd4ef3085); /* 43 */
	HH (b, c, d, a, x[ 6], S34,  0x4881d05); /* 44 */
	HH (a, b, c, d, x[ 9], S31, 0xd9d4d039); /* 45 */
	HH (d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */
	HH (c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */
	HH (b, c, d, a, x[ 2], S34, 0xc4ac5665); /* 48 */

	// Round 4
	II (a, b, c, d, x[ 0], S41, 0xf4292244); /* 49 */
	II (d, a, b, c, x[ 7], S42, 0x432aff97); /* 50 */
	II (c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */
	II (b, c, d, a, x[ 5], S44, 0xfc93a039); /* 52 */
	II (a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */
	II (d, a, b, c, x[ 3], S42, 0x8f0ccc92); /* 54 */
	II (c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */
	II (b, c, d, a, x[ 1], S44, 0x85845dd1); /* 56 */
	II (a, b, c, d, x[ 8], S41, 0x6fa87e4f); /* 57 */
	II (d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */
	II (c, d, a, b, x[ 6], S43, 0xa3014314); /* 59 */
	II (b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */
	II (a, b, c, d, x[ 4], S41, 0xf7537e82); /* 61 */
	II (d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */
	II (c, d, a, b, x[ 2], S43, 0x2ad7d2bb); /* 63 */
	II (b, c, d, a, x[ 9], S44, 0xeb86d391); /* 64 */

	m_state[0] += a;
	m_state[1] += b;
	m_state[2] += c;
	m_state[3] += d;

	// Zeroize sensitive information.
	memset( x, 0, sizeof(x) );
}

/// XMD5::Encode
/// Encodes input (uint4) into output (uint8). Assumes nLength is
/// a multiple of 4.
void XMD5::_encode(uint8 *output, const uint32 *input, uint32 inputLen)
{
	if (XByteOrder::native_type() == XByteOrder::ENDIAN_LITTLE)
	{
		memcpy(output, input, inputLen * 4);
	}
	else
	{
		for (uint32 i = 0, j = 0; i < inputLen; i++, j += 4)
		{
			output[j]	= (uint8)(input[i] & 0xff);
			output[j+1] = (uint8)((input[i] >> 8) & 0xff);
			output[j+2] = (uint8)((input[i] >> 16) & 0xff);
			output[j+3] = (uint8)((input[i] >> 24) & 0xff);
		}
	}
}

/// XMD5::Decode
/// Decodes input (uint8) into output (uint4). Assumes nLength is
/// a multiple of 4.
void XMD5::_decode(uint32 *output, const uint8 *input, uint32 inputLen)
{
	if (XByteOrder::native_type() == XByteOrder::ENDIAN_LITTLE)
	{
		memcpy(output, input, inputLen);
	}
	else
	{
		for (uint32 i = 0, j = 0; j < inputLen; i++, j += 4)
		{
			output[i] = ((uint32)input[j]) | 
				(((uint32)input[j + 1]) << 8) |
				(((uint32)input[j + 2]) << 16) | 
				(((uint32)input[j + 3]) << 24);
		}
	}
}


///////////////////////////////////////////////////////////////////////////////

void md5(const void* src, uint32 size, uint8 (&digest)[16])
{
	static const char* s_empty = "";
	memset(digest, 0, 16);
	if (src == NULL)
	{
		src = s_empty;
		size = 0;
	}

	XMD5 md5_;
	md5_.update((const uint8 *)src, size);
	md5_.final(digest);
	return;
}

string md5(const void* src, uint32 size)
{
	static const char* s_empty = "";
	if (src == NULL)
	{
		src = s_empty;
		size = 0;
	}

	XMD5 md5_;
	md5_.update((const uint8 *)src, size);
	return md5_.final();
}

} // namespace xcore


////////////////////////////////////////////////////////////////////////////////
// test section
////////////////////////////////////////////////////////////////////////////////

#ifdef _XCORE_NEED_TEST

#include "xcore_test.h"

namespace xcore
{

bool xcore_test_md5()
{
	string tmp = xcore::md5(NULL, 0);
	return true;
}

}//namespace xcore

#endif//_XCORE_NEED_TEST
